Alkylation of isoparaffin with olefins - by reacting first with low-strength hydrofluoric acid and then with stronger acid in soaking zone

摘要

A process for the alkylation of isoparaffins (esp. isobutane) with olefins (esp. propylene, butenes and pantenes) or olefin-acting agents (selected from propyl fluoride, butyl fluorides and pentyl fluorides) comprises (a) reacting the isoparaffin and olefin in admixture with a relatively low-strength (75-95 wt.%) HF catalyst, at a catalyst:hydrocarbon volume ratio of 1-5:1, (b) settling the reaction effluent to produce a hydrocarbon phase (I) and a catalyst phase, (c) admixing with (I) relatively high-strength (90-98 wt.%) HF and 2-10 wt.% of an organic diluent, at a lower catalyst: hydrocarbon volume ratio than in (a), (d) introducing the mixt. into a soaking zone and there isomerise low-octane alkylate to higher octane alkylate and convert alkyl fluorides to high-quality alkylate and HF, the soaking being effected at 50-120 degrees F for 5-20 minutes, (e) separating the effluent of the soaking zone into a second hydrocarbon phase (II) and a second catalyst phase, and (f) recovering alkylate product from (II). The process has a substantially radical catalyst inventory requirement, and provides alkylate of improved quality.